Thursday
November 19^th

Paul Zebell, Bill Kloos, and their colleagues in the Bureaus of Maintenance and Traffic Management maintain, modify, and repair the approximately 1,000 traffic signals at controlled intersections throughout the city.

Paul and Bill work with police, inspectors, citizens, traffic engineers, Tri- Met, and other public agencies to prioritize and orchestrate Portland's traffic flow.

While working to provide safe, reliable and efficient operation of the signals for vehicles, bicycles, and pedestrians, they also implement solutions to regional air pollution problems.

Paul and Bill reveal the secrets of… Timing - How signal timing accommodates the human factors and physics of driving, cycling, walking, and breathing. Detection - How traffic equipment detects cars, bicycles, and even people and what happens next. Cycles and sequences - Why what happens next isn't always the same. Fail-safe equipment design - How signals know what to do when something breaks. Preemption - How and why emergency and police vehicles and Tri-Met busses get higher priority.

Traffic Links For The Curious:

• Traffic Flow Theory: a state-of the art report
  
  
• Texas Transportation Human Factors Program
  
  
• USDOT general human factors reports
  
  
• Traffic Operations Control For Older Drivers And Pedestrians